Melvin B. Gottlieb, a pioneer physicist of the U.S. fusion program and an international leader in the field of research on fusion energy, died on December 1 in Haverford, Pa. He was 83.

Dr. Gottlieb, educated at the University of Chicago, was head of the experimental fusion research program in the mid-to-late 1950's at Princeton University where he was Professor of Astrophysical Sciences. From 1961-1980, he was Director of the Princeton Plasma Physics Laboratory. The Laboratory is the largest facility in the United States studying the physics of the high temperature gases, called plasmas, which are used to create fusion energy - an attractive energy source for the future.

Dr. Gottlieb led the Laboratory at a very exciting time. In the mid 1960's initial experimental results from the Soviet Union pointed to a new path to the very high temperature plasmas, or ionized gases, needed for making fusion energy. Under Dr. Gottlieb's leadership the Laboratory quickly extended these results, passing through three generations of highly successful "tokamak" experiments. The Tokamak Fusion Test Reactor, whose construction started under Dr. Gottlieb, created plasmas at nearly a billion degrees Fahrenheit, and made more than 10 million Watts of fusion power.

Dr. Gottlieb is remembered as much for his warm personal style as for his insightful scientific leadership. His thoughtfulness and calm - often expressed by putting his re-assuring arm around the shoulder of an over-stressed researcher - is a cherished memory at the Princeton Plasma Physics Laboratory.

In an interview in 1980 he was asked about the nation's energy options. He answered: "The long term solutions for energy are: fission, fusion, and solar. The question has always been: How much is it going to cost? If it costs ten times existing levels, we're obviously going to have a great deal of trouble supporting present population levels at the present standard of living. The attainment of an economic, environmentally acceptable energy source is of enormous importance for the future of mankind."

Dr. Gottlieb devoted considerable time during his career to working toward better understanding and cooperation with other nations in the development of fusion power. The fusion program at Princeton was classified until 1958. Thereafter the program became international, involving cooperation and sharing of information. Laboratory personnel including Dr. Gottlieb made frequent trips to meet with scientists abroad and encouraged extended visits to the U.S. by foreign scientists.

During his tenure as Director at the Princeton Plasma Physics Laboratory, Dr. Gottlieb was also involved in high-level discussions with government officials responsible for energy policy in many countries, including France, England, Germany, Italy, Norway, Japan, China, South Korea, Spain, Brazil, Canada, U.S.S.R., and the European Economic Community. He was a member of the U.S. Fusion Power Coordinating Committee; the U.S.-U.S.S.R. Joint Committee on Atomic Energy; the U.S.-People's Republic of China Committee on Fusion Cooperation; the U.S.-Japan Fusion Cooperation Committee. In 1971 he was a recipient of the North Atlantic Treaty Organization (NATO) Senior Foreign Fellowships in Science.

At the national level Dr. Gottlieb was active in many organizations whose purposes included finding alternative safe sources of energy and was for a time a member of Fusion Power Associates Board of Directors. He was a recipient of Fusion Power Associates first Distinguished Career Award in 1987. He had a long association with the American Physical Society and was founder and first chairman of its Plasma Physics Division. In 1980 he was Vice Chairman of its panel on Public Affairs (POPA). He was also a member of the American Nuclear Society and of Scientists and Engineers For Safe Energy.

After his retirement from the Laboratory, Dr. Gottlieb continued consulting in his field and, from 1980 - 1992, served as Chairman of the Nuclear Oversight Committee of the Public Service Electric and Gas Company of New Jersey.

Dr. Gottlieb is survived by his wife, Golda, of Haverford, Pa. whom he married in 1948; his daughter, Paula Bastian, of Cedar Run, N.J.; two grandchildren, Will Bastian and Mary Kate Bastian, and two nephews, David and Edward Mehlman, of Chicago. He was pre-deceased by his daughter, Martha, who died in an automobile accident in 1986.

Condolences may be sent to his wife, Mrs. Golda Gottlieb, 3300 Darby Road, Haverford, PA 19041-1066